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<div class="titlepage"><div><div><h3 class="title">
<a name="spirit_x3.quick_reference.non_terminals"></a><a class="link" href="non_terminals.html" title="Nonterminals">Nonterminals</a>
</h3></div></div></div>
<div class="variablelist">
<p class="title"><b>Notation</b></p>
<dl class="variablelist">
<dt><span class="term"><code class="computeroutput"><span class="identifier">Attr</span></code></span></dt>
<dd><p>
              Synthesized attribute. The rule return type.
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">ID</span></code></span></dt>
<dd><p>
              The rule ID
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">r</span><span class="special">,</span>
          <span class="identifier">r2</span></code></span></dt>
<dd><p>
              Rules
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">r_def</span><span class="special">,</span>
          <span class="identifier">r2_def</span></code></span></dt>
<dd><p>
              A rule definition. By convention a rule named <code class="computeroutput"><span class="identifier">r</span></code>
              should have corresponding rule definition named <code class="computeroutput"><span class="identifier">r_def</span></code>
            </p></dd>
<dt><span class="term"><code class="computeroutput"><span class="identifier">p</span></code></span></dt>
<dd><p>
              A parser expression
            </p></dd>
</dl>
</div>
<div class="informaltable"><table class="table">
<colgroup>
<col>
<col>
</colgroup>
<thead><tr>
<th>
                <p>
                  Expression
                </p>
              </th>
<th>
                <p>
                  Description
                </p>
              </th>
</tr></thead>
<tbody>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">rule</span><span class="special">&lt;</span><span class="identifier">ID</span><span class="special">,</span>
                  <span class="identifier">Attr</span><span class="special">&gt;</span>
                  <span class="keyword">const</span> <span class="identifier">r</span>
                  <span class="special">=</span> <span class="identifier">name</span><span class="special">;</span></code>
                </p>
              </td>
<td>
                <p>
                  Rule declaration. <code class="computeroutput"><span class="identifier">ID</span></code>
                  is required. <code class="computeroutput"><span class="identifier">Attr</span></code>
                  is optional and defaults to <code class="computeroutput"><span class="identifier">unused_type</span></code>.
                  <code class="computeroutput"><span class="identifier">name</span></code> is an optional
                  string that gives the rule its name, useful for debugging and error
                  handling.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">r</span><span class="special">.</span><span class="identifier">name</span><span class="special">()</span></code>
                </p>
              </td>
<td>
                <p>
                  Getting the name of a rule
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="keyword">auto</span> <span class="keyword">const</span>
                  <span class="identifier">r_def</span> <span class="special">=</span>
                  <span class="identifier">p</span><span class="special">;</span></code>
                </p>
              </td>
<td>
                <p>
                  Rule definition
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">BOOST_SPIRIT_DEFINE</span><span class="special">(</span><span class="identifier">r</span><span class="special">,</span> <span class="identifier">r2</span><span class="special">,</span> <span class="special">...)</span></code>
                </p>
              </td>
<td>
                <p>
                  Links one or more rules (<code class="computeroutput"><span class="identifier">r</span><span class="special">,</span> <span class="identifier">r2</span><span class="special">,</span> <span class="special">...</span></code>)
                  with their definitions (<code class="computeroutput"><span class="identifier">r_def</span><span class="special">,</span> <span class="identifier">r2_def</span><span class="special">,</span> <span class="special">...</span></code>)
                </p>
              </td>
</tr>
</tbody>
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<td align="right"><div class="copyright-footer">Copyright © 2001-2018 Joel de Guzman,
      Hartmut Kaiser<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
      </p>
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